Previously, electronic devices such as portable phones and digital cameras use mechanical switches, such as tactile switches and membrane switches, as an input unit enabling users to perform manipulation input. Specifically, recently, there are many small terminal devices having a variety of functions, and these terminal devices includes keys, buttons, and the like made of various kinds of switches on their faces.
As for these switches, in general, one operation (or program) is assigned to one switch. For example, in a case of a portable phone, when a pressing input to a numeral keypad is detected, a number corresponding to each key is output. Alternatively, when a pressing input to a numeral keypad is detected, a menu screen is displayed.
However, for example, in a case where it is desired to sequentially perform a plurality of operations, when each operation is performed using a separate switch to which the corresponding operation has been assigned, a lot of trouble may be required. For this reason, it is possible to consider a configuration in which one switch is used to perform operations in order whenever an input to the switch is detected. However, in this input type, the order in which the operations are performed is to be defined in advance. Therefore, it is impossible for a user to perform manipulation for immediately performing a desired arbitrary operation.
In order to solve the above-mentioned problem, there has been proposed an input device capable of assigning a plurality of operations based on input types to one switch (see, for example, Patent Document 1).
The input device disclosed in Patent Document 1 can accept inputs in two levels based on pressing loads regarding inputs when manipulation is performed.
FIG. 8 is a cross-sectional view schematically illustrating an internal configuration of a manipulation device 100 disclosed in Patent Document 1. As shown in FIG. 8, the manipulation device 100 includes a first detecting unit 200, a second detecting mean 300, and membrane switches, and the second detecting mean 300 is provided below the first detecting unit 200 (in a pressing direction). A portion to be directly touched by a finger F of a user is made of a flexible member, and when the user presses the manipulation device 100, the flexible member bends so as to transfer the pressing load to the first detecting unit 200. When the user presses a position corresponding to a first contact point S3 with the finger F with a low weight (a first manipulation force), a first upper conductive portion 201c and a first lower conductive portion 202c come into contact with each other, so that the first contact point S3 becomes conductive. This is considered as a first-level input. Also, when the user presses the corresponding position with the finger F with a high weight (a second manipulation force) larger than the low weight, a second upper conductive portion 301c and a second lower conductive portion 302c come into contact with each other, so that a second contact point T3 becomes conductive. This is considered as a second-level input. Furthermore, FIG. 8 shows a situation in which the manipulation device 100 was pressed by the second manipulation force of the finger F of the user, and thus the first contact point S3 detects not only the first-level input and the second contact point T3 also detects the second-level input.
This input device accepts user's inputs in two levels based on the pressing loads of the inputs, and thus it is possible to assign different operations to those individual levels. In a case of using this input device, the user can use one switch (input device) to differentially perform a plurality of inputs by adjusting a pressing force when performing one operation of performing a pressing input to the switch.
In other words, according to this input device which accepts two-level inputs, the user can perform a first-level input by keeping a state in which a button is pressed by a weak pressing force. This input state is called ‘a half-press’, and is hereinafter referred to as ‘a first-level input’. Further, according to this input device, the user can perform a second-level input by pressing the button with a pressing force stronger than that of the first-level input. This input state is called ‘a full-press’, and is hereinafter referred to as ‘a second-level input’.
As an example of the typical purposes of that input device which accepts inputs in two levels based on pressing loads by a mechanical switch, there is a shutter button of a camera. In general, in a portable terminal or the like having a digital camera function and the like, a user performs a ‘half-press’ input as a first-level input, thereby enabling an imaging process. In this state, the user performs a ‘full-press’ input as a second-level input, thereby performing an operation of clicking the shutter. In this way, it is possible to assign different operations by the first-level input and the second-level input, and the user can distinguish the different operations and perform manipulation according to a desired operation.
Also, the input device which accepts multi-level inputs based on pressing loads is not limited to the mechanical switch. For example, as for a touch panel type input device configured by combining a display device and a position input device, there has been suggested an input device which accepts multi-level inputs based on pressing loads by performing a process according to software (see, for example, Patent Document 2).
A touch panel type input device disclosed in Patent Document 2 includes a position detecting unit detecting a pressed position of a touch panel provided to a face portion of a display screen, and a pressure detecting unit detecting a pressing force on the touch panel. In this input device, it is possible to perform inputs of two systems, i.e. an input based on a detection position of the position detecting unit, and multi-level inputs based on the detection of the pressure detecting unit, by one time pressing manipulation on the touch panel.
According to this input device, when a user presses the touch panel on the display screen, it is possible to perform an input of a first system based on the pressed position, and at the same time, it is possible to perform an input of a second system based on the pressing force on the touch panel at that time. Then, based on the pressing force on the touch panel, selection of multiple levels, that is, three or more levels becomes possible. Therefore, the user can perform inputs of two systems by performing pressing manipulation on the touch panel once, and thus it is possible to reduce the number of times pressing manipulation.
As described above, even in an input device using a mechanical switch, and even in an input device using a touch panel, it is possible to accept inputs in a plurality of levels based on pressing loads. In this input device, since inputs are distinctively accepted in a plurality of levels based on pressing loads, it is possible to group a plurality of functions for one button or key. Therefore, it is possible to reduce the number of keys and buttons regarding manipulation inputs. Specifically, in a case of small terminals like portable terminals, since a case of each individual terminal is small, it is difficult to provide a lot of keys and buttons to the main body of the terminal. Therefore, in a portable terminal, when it is possible to properly use a plurality of functions by using a few keys and buttons, it is possible to reduce keys and buttons which is to be provided to the main body of the terminal.